Numerous industries and applications use tooling fixtures to restrain a workpiece for manufacturing operations. Typical uses of tooling fixtures include securing and clamping raw stock to a machine for manufacturing operations, such as machining, milling, welding and other such manufacturing operations. In many cases the same tooling fixture is used throughout the various manufacturing operations. Tooling fixtures are also used on finished parts that are being assembled into subassemblies and final assemblies. Workpiece refers to the various parts that tooling fixtures restrain.
Existing methods to restrain a workpiece generally include clamping, bolting, or other forms of securing the workpiece to the operating surface of the tooling fixture. One such method uses bolts in which the threaded portion extends above the operating surface of the tooling fixture. These bolts reside in a cavity formed in the underside of the tooling fixture, and include a conical spring to bias the bolt in an extended position. A plug, accessible only from the underside of the tooling fixture, secures the bolt and spring in the cavity.
The workpiece to be secured typically includes threaded holes that align with the bolts extending from the tooling fixture. To secure the workpiece, a drive device engages a drive socket in the threaded portion of the bolt and rotates the bolt. The spring provides a biasing force to help the bolt engage the threaded hole in the workpiece. The drive device tightens the bolt, thereby securing the workpiece to the tooling fixture.
Existing bolt assemblies suffer from numerous disadvantages. One such disadvantage is that replacement of a damaged bolt requires removal of the tooling fixture/workpiece assembly from the machine or assembly tool to access the plug that secured the bolt in the cavity. This causes an interruption in the fabrication process, which may increase the time and cost to produce the finished product. In addition, replacement of damaged bolts may disturb the indexed orientation of the workpiece on the machine. In many cases, the workpiece will be scrapped due to the disruption. A further disadvantage with prior bolt assemblies is that unused bolts extend above the operating surface of the tooling fixture, thereby interfering with access to the workpiece and causing a safety hazard.